Fellow introvert here, and long-time lurker myself. Welcome! Glad you came out of the shadows.
Where are you staying on your trip? Will it be easy to take a midday break? How interested are you in seeing other resorts? At that time of year, it’ll probably be kind of chilly for swimming. I guess I’m trying to gauge how much interest you have in non-park activities…
Honestly, for a trip of that length–and under your circumstances–I’d be tempted to do as much as I could. That being said, are you and your husband on the same page as far as enthusiasm and energy goes? I know my husband needs a midday break or Disney’s no fun for him. Whereas I could go from sunup to sundown, no problem.
If you’re a planner, then maybe you could make a list of attractions that are 1)must-dos, 2)would-like-to-dos, and 3)only-if-there’s-time. That first week of February should be good for crowds, unless I’m missing something, so you might get more done than you think. Then you’ll be able to really relax. Speaking for myself, it’s fine to talk about “slowing down and smelling the roses,” but if there’s something I still want to do out there . . . well, I want to go do it.
Remember that outside of Flight of Passage, and Seven Dwarfs Mine Train, you’ll probably be able to switch up your FPs while there, if you need to shift your park days around. In that way, you can keep things open and flexible.
It might be nice to spend a longer period of time in World Showcase, since it’s just you guys. I always feel like we have to rush through that area a little because our kids aren’t as interested. Maybe make an ADR for Spice Road Table or Rose & Crown 90 minutes before Illuminations starts, so you can watch the fireworks after eating. That would be romantic.
I hope you have a great time! It sounds like this trip has been a long time coming.